Allow CI failures on Julia nightly builds (#776)

Author: c42f

.github/workflows/ci.yml

@@ -9,6 +9,7 @@ jobs:
   test:
     name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }}
     runs-on: ${{ matrix.os }}
+    continue-on-error: ${{ matrix.version == 'nightly' }}
     strategy:
       matrix:
         version: